The present disclosure relates to a position estimation apparatus, a position estimation method, a program, and a position estimation system.
Recently, receiver apparatuses capable of receiving wireless signals transmitted from satellites have been installed in moving bodies such as vehicles, mobile telephones, and the like. By using GPS (Global Positioning System) positioning, it is possible to estimate the position of the moving body in which the receiver apparatus is installed. Such position estimating technology that uses a receiver apparatus is an important base technology in a wide range of fields such as navigation, security and entertainment.
Further, a position estimation method is also conceivable according to which a wireless terminal that performs wireless communication with a base station (an access point) on a wireless LAN (Local Area Network) measures the signal strength of a signal transmitted from a wireless base station and a position estimation apparatus that is capable of communicating with the wireless terminal estimates the position of the wireless terminal based on this signal strength. For example, the base station of the wireless LAN transmits beacons for notifying a surrounding area of the existence of the base station of the wireless LAN at predetermined intervals (for example, 5 times/sec). The wireless terminal transmits the signal strength of such a beacon to the position estimation apparatus, and the position estimation apparatus can estimate the position of the wireless terminal based on the signal strength and the position of the base station of the wireless LAN that is registered in advance. With the above-described position estimation method, since the base stations of the wireless LAN are installed in indoor and underground environments, it is possible to perform position estimation in indoor or underground environments, which is difficult using the position estimation technology based on the GPS positioning.
In this type of position estimation method, when a user carrying a wireless terminal is present in a building or structure, not only the latitude and longitude of the wireless terminal, but also information indicating which area (for example, which floor) in the building or structure the user is currently in is important. For example, JP 2005-229617A discloses a technology according to which a wireless terminal measures signal strengths of wireless signals transmitted from a plurality of base stations, and a position estimation server estimates that the wireless terminal exists in an area where a base station which is the transmission source of a wireless signal with a strong signal strength is present.